Ground Anchors

285 Pages·2008·11.81 MB·English

PROCEEDINGS INTERNATIONAL SYMPOSIUM

GROUND ANCHORS
Limelette test field results

VOLUME 1

14 May 2008
Hotel Métropole – Brussels

BGGG - GBMS BBRI

Proceedings of the International Symposium
“Ground Anchors – Limelette test field results”
14 May 2008, Brussels, Belgium
Volume 1

TABLE OF CONTENTS

PREFACE

INTRODUCTORY ADDRESS

ORGANISATION

WORKING GROUP “GROUND ANCHORS”

AKNOWLEDGEMENTS

CONTRIBUTIONS
General Framework and Viewpoint with regard to Ground Anchors, Soil Nails and
Tension Piles
Prof. J. Maertens (Jan Maertens bvba & K.U. Leuven)

Ground Anchors : Overview of Types, Installation Methods and Recent Trends
Ir. F. De Cock (Geo.be)

Full Scale Load Test Program in Limelette : Overview of the Test Campaign, Set up &
General Results
Ir. N. Huybrechts & Ir. O. Tomboy, (BBRI), Prof. J. Maertens (Jan Maertens bvba &
K.U. Leuven) & Prof. A. Holeyman (UCL)

Excavation of the Anchors : Measurements and Observations
Ir. O. Tomboy & Ir. N. Huybrechts (BBRI)

Integrated Analysis of the Load Test Results & Suggestions for a Harmonised Anchor
Design and Test Methodology in Belgium in the Eurocode 7 Framework
Ir. N. Huybrechts, Ir. M. De Vos & Ir. O. Tomboy (BBRI) & J. Maertens (Jan Maertens
bvba & K.U. Leuven)

Practical Experience of TUC RAIL with Ground Anchors and Micro-Piles
Ir. W. Maekelberg, Ir. Q. Bollens, Ir. J. Verstraeten, Ir. F. Theys, E. De Clercq
(TUC RAIL) & Prof. J. Maertens (Jan Maertens & Partners bvba & K.U. Leuven)

Experience with Ground Anchors of the Federal Public Buildings Service
Ir. Ph. Debacker (Federal Public Buildings Agency)

Experience with Ground Anchors of the Flemish Ministry
Ir. I. Mariën (Ministry of Flemish Community)

Design Guidelines for Non-driven Tension Piles Underneath under Water Concrete
Slabs
Ir. A.C. Vriend, reporter C-152 & Acécon (NL)

Experience in France with Ground Anchors
Prof. J.P. Magnan (LCPC, F)

Application of Ground Anchors, Nails and Tension Piles in Europe and Current Status
of the EN 1537 – Ground Anchors
Dr.-Ing. W.R. Linder Chairman of CEN TC 288 Execution of Special Geotechnical
Works & Brückner Grundbau (DE)
Dr. Caesar Merrifield, Convener of CEN TC 288 WG 14 “Anchors” & Coffey
Geotechnics (UK)

PREFACE

Ground anchors are commonly used in Belgium in different building and civil
engineering applications (anchorage of retaining walls, submerged structures, quay
walls, stabilisation of slopes, …). Unfortunately, up to now no Belgian geotechnical
standards, which deal with such elements, exist. As a consequence, the project
specifications of different owners integrate generally, without coherence, different
design and test methodologies coming from other countries, mostly from French and
German standards.
In addition a lot of new anchoring techniques, for which the current geotechnical codes
are in general not yet adapted, appeared the last decade on the Belgian market.
Particular situations are those where not all the anchors are tested and/or pre-stressed.
Finally, within the framework of the European standardisation, which is fully
developing, the construction sector experienced a strong need for a better understanding
of the applied anchoring techniques and appropriate design methods, in particular for
the establishment of the Belgian national annex of the Eurocode 7.

All the above-mentioned aspects encouraged the Belgian Building Research Institute
(BBRI - CSTC - WTCB) to undertake the establishment of a uniform guidance for the
execution, the design and the testing of anchoring systems in Belgium. In order to
address this issue the BBRI initiated in 2004 a national research project on ground
anchors. The project is guided by an inter-professional Working Group under
supervision of the project partners K.U. Leuven (Prof. J. Maertens) and UCL (Prof. A.
Holeyman). Financial support for the research project has been obtained from the
Belgian Federal Public Service “Economy” and the Belgian Normalisation Institute.
Backbone of the research project is the extended real scale load test campaign on
approximately 50 ground anchors performed at the proof station of the BBRI in
Limelette.

During this symposium the various aspects of this extended load test campaign in
Limelette (B) will be reviewed : soil investigation, anchor installation methods, load
testing and interpretation, as well as observations related to the excavated anchors.
Suggestions for an approach to design and test ground anchors in Belgium following the
Eurocode 7 principles will be put forward.
Moreover attention will be paid to the experience with ground anchors of three main
organisations on the Belgian building market: Tuc Rail, the Federal Public Buildings
Service, and the Ministry of the Flemish community.
Finally three contributions from neighbouring countries (NL, F & DE) will deal with
developments in anchoring techniques and design approaches in their country and/or in
Europe.

It is the hope of the organizers that the results of the Limelette load test campaign and
the discussions held during this international symposium might be of value in the
development of European geotechnical standardization.

The organization committee

INTRODUCTORY ADDRESS
Research has historically been performed in Belgium by common efforts of independent
bodies and individual contractors. It is only recently that the BBRI introduced the
concept of more “global” research projects starting a few years ago with the research on
screw piles, and the development of new guidelines for the design of piled foundations
in the frame of the NAD of the EC7. In this context, the creation of the Belgian
Federation of Foundations Contractors (ABEF) has filled in a gap as corresponding
partner to the BBRI and other Federal bodies, in order to globalize the reflections and
interests of the Foundation Industry, as a whole. This can be considered as a major
achievement and a clear progress towards the past.
Until recently, as stated by Noël Huybrechts, Belgium was characterized by the absence
of codes or guidelines. This situation, which the contractors relatively easily could deal
with, was judged, with some reason, dangerous and difficult by administrations and
consulting offices. It was also difficultly compatible with the introduction of the
European codes and norms. The BBRI has launched several projects in order to
remediate this situation, inscribing its efforts in the global perspective of the Eurocodes.
ABEF naturally contributed to consolidate the Contractor’s views, adding some
entrepreneurial perspective to these efforts.
ABEF was created in 1998 by 6 founding members, gathering the biggest contractors in
the field of Deep Foundations. It has welcomed in the meantime 6 new members, and
currently represents 80 % of the Belgian Deep Foundations market. Establishing a solid
base for sound competition and reliable and safe execution of deep foundations is our
global objective. Contributing to this research is part of this global objective.
Other concrete steps over the last years are:
o Work out a specific education program for workmen of the different members
together with VDAB/FOREM structured around 3 modules corresponding to 3
levels of education.
o Develop common Working Conditions in order to improve the contractual and
technical quality of the relationship with the clients/general contractors.
o Actively participate in the different working groups and research programs
• TIS
• National Annex of the Eurocode 7 (piles)
• Research Program on Screw Piles
• Research Program on retaining walls
o Participate in the activities of the European Federation of Foundation Contractors
and other international Working Groups
• TC288: Bored piles and Slurry Walls
• Contract & Qualification Working Group of the EFFC
As President of ABEF, I am particularly pleased to welcome you all, to this seminar.
What will be presented today is the result of years of efforts, installation and testing
which the Deep Foundation Industry has contributed to both financially and
intellectually. We hope you will benefit of this investment. Enjoy your stay in
Brussels.

ir Maurice Bottiau
ABEF – President
BGGG/GBMS – Vice-President
Franki Foundations Group Belgium – Group Commercial Director